Conventionally, as a liquid processing apparatus which performs a liquid processing on a substrate such as a semiconductor wafer or a glass substrate, there is known a single-wafer type liquid processing apparatus. The single-wafer type liquid processing apparatus includes, for example, a substrate holding unit configured to rotate the substrate while holding an outer peripheral portion of the substrate; and a supply unit configured to supply a processing liquid onto a top surface of the substrate held by the substrate holding unit.
In this liquid processing apparatus, it is required to suppress the processing liquid supplied onto the top surface of the substrate from flowing onto a bottom surface of the substrate. In this regard, recently, there is proposed a liquid processing apparatus in which the substrate is held on an inclined surface which is extended along the circumference of the substrate and the bottom surface of the substrate and the inclined surface are in contact with each other along the substantially entire circumference of the substrate. With this configuration, the processing liquid can be suppressed from flowing from the top surface of the substrate onto the bottom surface thereof.
If, however, the substrate is bent, a minute gap may be formed between the substrate and the inclined surface, and the processing liquid may flow toward the bottom side of the substrate through this minute gap. As a result, in the above liquid processing apparatus, a liquid residue may be generated at a peripheral portion of the bottom surface of the processed substrate.
Meanwhile, Patent Document 1 describes a liquid processing apparatus in which spherical supporting members are provided on the inclined surface and the substrate is supported by these supporting members. To elaborate, the spherical supporting members are arranged to support positions of the bottom surface of the substrate distanced 1 mm to 2 mm away from an outer edge of the substrate toward a center thereof.
Patent Document 1: Japanese Patent Laid-open Publication No. 2010-093190
In the structure described in Patent Document 1, however, when performing a liquid processing on the substrate with a pattern forming surface thereof facing downwards (that is, the pattern forming surface serves as the bottom surface), it may be difficult to place the substrate accurately, and interference between the supporting members and the pattern forming surface may occur.